Resin intake manifold

ABSTRACT

A resin intake manifold is provided with a surge tank, an independent intake passage connected to the surge tank, and a plurality of pieces formed in a predetermined shape and welded along a weld line. A funnel portion is formed in a portion connected from the surge tank to the independent intake passage, and the weld line is formed so as to cross over a portion near the funnel portion. A funnel partition wall separating a plurality of independent intake passages is formed in the funnel portion so as to protrude from one piece to another piece. A funnel wall receiving portion receiving the funnel partition wall is formed in another piece, and the funnel partition wall and the funnel wall receiving portion are welded in bonded surfaces.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Japanese patent applicationof Tanikawa et al. filed Apr. 11, 2003, No. 2003-108261, and JapanesePatent Application of Tanikawa filed Apr. 9, 2003, No. 2003-105265, andJapanese patent application of Tanikawa filed Apr. 10, 2003, No.2003-106570, the entirety of each is hereby incorporated into thepresent application by this reference.

The present application is a Divisional Application of the patentapplication Ser. No. 11/266,194, filed on Nov. 4, 2005, which is basedon U.S. patent application Ser. No. 10/811,985, filed on Mar. 30, 2004,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a synthetic resin intake manifold usedin an internal combustion engine for a motor vehicle, and moreparticularly to a resin intake manifold manufactured by connectingprotrusions of weld portions of at least two separated bodies to eachother in accordance with a vibration welding or the like.

2. Description of Related Art

Conventionally, a resin intake manifold is manufactured by vibrationwelding protrusions in welded portions of a plurality of separatedbodies to each other, for example, as described in Japanese UnexaminedPatent Publication No. 9-177624.

However, there is a case that set reference surfaces in the weldportions of the separated bodies are arranged in a curved shape or aninclined state, in accordance with a die cutting direction at a time ofmolding the separated bodies and a connecting direction between theseparated bodies. Further, in some vibrating directions of the vibrationwelding, a burr (a weld burr) B is generated more than a predeterminedamount at a time of welding protrusions 3 and 7 of weld portions 2 and 6in separated bodies 1 and 5 to each other, as shown in FIG. 1A, andthere is a case that the burr B protrudes over a cover wall 4 arrangedin the periphery of the protrusions 3 and 7.

The burr B getting over the cover wall 4 is hard to be viewed if itappears in an inner side (an inner peripheral side) of the intakemanifold. Accordingly, it takes a lot of trouble with checking out theburr. If the intake manifold is mounted to a vehicle in a state in whichthe burr B is left in the inner peripheral side, and is used, and theburr B is peeled away together with passing of an intake fluid, there isa risk that the burr flows to an engine side so as to be attached to avalve or the like, thereby generating an obstacle in a valve closingoperation, so that this phenomenon is not preferable.

Further, if the burr B appears in an outer peripheral side of the intakemanifold, an outer appearance design of the intake manifold is lowered,and this phenomenon is neither preferable.

Accordingly, it is necessary to check out presence of the burr B.Further, if the burr B is generated, it is necessary to carry out anextra finishing work such as a grinding work or the like for removingthe burr B, thereby increasing a manufacturing man-hour and cost of theresin manifold. Therefore, it has been desired to easily prevent theburr generated at a time of vibration welding from being exposed to theinner peripheral side or the outer peripheral side of the product.

On the other hand, in the conventional resin intake manifold, it isdesirable in view of a manufacturing man-hour and cost to integrallyform a tank chamber such as a resonator or the like, in comparison withthe case that the tank chamber is formed as an independent body.

However, in the case that the tank chamber has a large capacity, forexample, it is necessary to form the tank chamber by adding the otherpieces to two main pieces constituting the intake manifold, it is hardto secure a strength of each of the weld portions unless the weldportions of at least three pieces are properly arranged. In this case,it is reversely necessary to use a slide jig or the like so as to securea proper welding strength, so that the manufacturing man-hour and costare increased.

In accordance with the structure mentioned above, for example, as shownin FIG. 1B, there is exemplified a structure in which a first piece 101and a second piece 105 are welded, an intake flow passage is formed at aposition (not shown), the first piece 101 is provided with a tubularperipheral wall portion 104 forming a tank chamber 107 capable ofstructuring a resonator, and a third piece 106 is arranged as a covermember closing an end portion of the peripheral wall portion 104. Inaccordance with the structure mentioned above, in the first piece 101, acollar portion 102 for welding to the second piece 105, and a collarportion 103 for welding to the third piece 106 are arranged in both endportions of the tubular peripheral wall portion 104.

However, in the structure mentioned above, among pressurizing jigs 108and 109 for pressurizing and supporting at a time of vibration weldingthe first piece 101 and the third piece 106, the pressurizing jigs 109and 109 for supporting the collar portion 103 are structured such as toslide in an orthogonal direction to an axis of the peripheral wallportion 104 for preventing the pressurizing jigs 109 and 109 from beinginterfered with the collar portion 102, so that the structure of thepressurizing jigs 109 and 109 is complex, thereby increasing the weldingcost. Further, since the pressurizing jig 109 supports in a cantileverstate, it is hard to obtain a sufficient welding strength, it isnecessary to make a welding time long to devise a countermeasure, and alot of welding man-hour is required.

Further, since the conventional resin intake manifold is formed inaccordance with a synthetic resin injection molding using a molding dieat a time of manufacturing the resin intake manifold, the resin intakemanifold is formed by being separated into a plurality of pieces, asdescribed in Japanese Unexamined Patent Publication No. 8-252864. Inparticular, a portion running into an independent intake passage from asurge tank via a funnel portion is formed in a state of being separatedas another piece. Further, in the case that the resin intake manifold isformed in a state of being separated into a plurality of pieces, thepieces are welded by weld lines corresponding to bonded portions inaccordance with a vibration welding after being molded, whereby anentire resin intake manifold is manufactured.

However, in this kind of resin intake manifold, in the case that theweld line is formed so as to cross over in the portion running into theindependent intake passage from the surge tank via the funnel portion, astep portion tends to be generated in the weld portion, and in the casethat the step portion is formed so as to cross over a communicationpassage of the funnel portion perpendicularly, a turbulence is generatedin an intake air flow in the portion, and a ventilation resistance ofthe intake air is increased.

Further, in the case that the separated pieces are welded in the weldline and the intake manifold is integrally formed, if the weld line isformed two-dimensionally or flat, the weld line is formed so as to bepositioned within one flat surface, so that in the case that a vibrationfrom the engine and a vibration pressure caused by an intake pulsationare applied at a time of being attached to the engine and used, apressure resisting strength and a vibration resisting strength in theweld line tend to be lowered.

SUMMARY OF THE INVENTION

A first object of the present invention is to provide a resin intakemanifold which can easily prevent a burr generated at a time ofvibration welding from being exposed to an inner peripheral side and anouter peripheral side of a product.

The first object can be achieved by a resin intake manifold having thefollowing structure. In other words, the resin intake manifold isprovided with at least two separated bodies manufactured by connectingprotrusions of weld portions of the separated bodes to each other inaccordance with a vibration welding, and a cover wall in which one ofthe weld portions is arranged in an inner side or an outer side of theprotrusion with leaving space with the protrusion, and structured suchthat the protrusions of the weld portions are respectively provided withparallel protrusion portions extending in parallel to a vibratingdirection of the vibration welding, a cover wall arranged at a positionin an orthogonal direction to the vibrating direction in the parallelprotrusion portions is provided with an extension portion extending tothe separated body in the other side welded to the separated bodyprovided with the cover wall, in such a manner as to prevent a burrgenerated at a time of welding the parallel protrusion portion fromgetting over the cover wall arranged at the position in the orthogonalto the vibrating direction in the parallel protrusion portion, and arecess groove receiving the extension portion is arranged in a side ofthe other side separated body.

In the resin intake manifold in accordance with the present invention, alot of burrs are generated in the portion of the parallel protrusionportion at a time of vibration welding the protrusions in the weldportions of the corresponding separated bodies to each other. However,even when the burr is going to extend in an approximately orthogonaldirection from the parallel protrusion portion so as to get over thecover wall during a welding step, the extension portion extending to theother side separation body welded to the separation body provided withthe cover wall is formed in the cover wall, and the extension portionstops the burr and prevents the burr from being exposed to the innerside or the outer side of the intake manifold.

Further, since the extension portion is arranged in the recess groove ofthe other side separation body after the welding is finished, and cankeep the burr in the space in the side of the parallel protrusionportion of the extension portion, it is possible to prevent the burrfrom being scattered even in the case that the burr is arranged in theinner side of the intake manifold.

Accordingly, in the resin intake manifold in accordance with the presentinvention, it is possible to easily prevent the burr generated at a timeof vibration welding from being exposed to the inner peripheral side orthe outer peripheral side of the product, only by arranging theextension portion, and it is possible to prevent the burr from beingscattered. Accordingly, it is possible to reduce the manufacturingman-hour and cost, at such a degree that the inspection of presence ofthe burr and the removing process can be simplified. Of course, even inthe case that the set reference surfaces of the weld portions in theseparated bodies are formed in a curved shape or in an inclined state,the burr is not exposed to the inner peripheral side or the outerperipheral side of the product. Accordingly, it is possible to freelyset the die cutting direction at a time of molding the separated bodyitself and the connecting direction between the separated bodies withoutconstraints caused by the burrs, and it is possible to improve a designfreedom of the separated bodies.

Further, the structure may be particularly made such that the resinintake manifold is provided with a plurality of distribution passagescapable of flowing an intake fluid so as to integrally put base portionsides together and separate leading end portion sides into a pluralityof sections, two separated bodies are constituted by a cover memberforming an outer wall of each of the distribution passages, and a basemember welded to the cover member and forming each of the distributionpassages together with the cover member, and the cover member isprovided with an assembled portion integrally covering the base portionsides of the respective distribution passages, and branch portionsarranged so as to extend from the assembled portion to the leading endportion sides of the respective distribution passages and separated fromeach other in correspondence to the number of the respectivedistribution passages. In this case, it is desirable that the vibratingdirection at a time of vibration welding is set to a direction extendingalong the parallel arranging direction of the respective distributionpassages, and the parallel protrusion portion and the cover wallprovided with the extension portion are arranged at a leading end ofeach of the branch portions in the cover member.

In other words, the cover member is welded to the weld portion of theother side base member in a state in which an entire area of the weldportion including the assembled portion and the respective branchportions are pressurized and supported by the pressurizing jig used forthe vibration welding at a time of vibration welding. However, theleading end sides of the respective branch portions are separated witheach other and tend to be dispersed in a dimensional accuracy, incomparison with the assembled portion, so that a dispersion is generatedin a weld margin at a time of welding. Accordingly, in addition to theparallel protrusion portion in which the burr tends to be generated, theportion generating the burr tends to be further generated. However,since the cover wall provided with the extension portion is arranged inthe portion in which the burr tends to be generated, it is possible toaccurately cover the burr. Of course, the vibrating direction at a timeof welding is set to the direction extending along the parallelarranging direction of the respective distribution passages in place ofthe direction extending along the respective distribution passage.Accordingly, even in the case that the respective distribution passagesare arranged spirally in the outer peripheral side of the intakemanifold from an upstream side of the intake fluid to a downstream side,it is possible to weld the cover member to the base member by smoothlyvibrating the cover member.

Further, the structure may be made such that the cover wall providedwith the extension portion is arranged in the side of each of thedistribution passages in the parallel protrusion portion. In accordancewith the structure, there is no risk that the burr is scattered withinthe distribution passage, and it is possible to prevent an enginetrouble caused by the burr.

A second object of the present invention is to provide a resin intakemanifold which can be manufactured while restricting an increase of amanufacturing man-hour and cost, even in the case that a tank chamberformed over three welded pieces is integrally provide.

The second object can be achieved by the resin intake manifold havingthe following structure. In accordance with the present invention, thereis provided a resin intake manifold manufactured by welding at leastthree separated first, second and third pieces while pressurizing, andprovided with a tank chamber communicated with a part of a flow passageof an intake fluid and formed by the first, second and third pieces,wherein the first and second pieces are structured such as to be weldedto each other for forming the flow passage of the intake fluid, thefirst piece is provided with a tubular peripheral wall portion commonlyusing a wall portion forming the intake flow passage and constitutingthe tank chamber, the second piece is provided with a ceiling wallportion covering one end portion side of the peripheral wall portion,the third piece is structured as a cover member closing another endportion side of the peripheral wall portion, an outer weld collarportion for welded to the second piece is arranged in an outerperipheral edge of the first piece including the peripheral wall portionso as to be formed to protrude to an outer side, and a portion weld tothe third piece in the first piece is provided with an inner weld collarportion protruding to the inner peripheral wall surface of theperipheral wall portion in such a manner as to prevent an interferencewith a pressurizing jig supporting the outer weld collar portion at atime of welding the first piece and the second piece.

In other words, in the resin intake manifold in accordance with thepresent invention, even in the case that one end portion of theperipheral wall portion in the first piece is provided with the outerweld collar portion for welding to the second piece, the weld portion tothe third piece in another end portion of the peripheral wall portion isformed as the inner weld collar portion which can prevent theinterference with the pressurizing jig supporting the outer weld collarportion at a time of welding the first piece to the second piece.

Further, at a time of welding the first piece and the third piece, theinner weld collar portion of the peripheral wall portion can besupported by the pressurizing jig arranged in the inner peripheral sideof the peripheral wall portion, and the pressurizing jig can be formedby a simple structure which is not necessary to be slid. Accordingly,since a welding cost is not increased and the inner weld collar portioncan be firmly supported in the inner peripheral side of the peripheralwall portion, it is not necessary to make a weld time too long and awelding man-hour is not increased.

Of course, since the first piece can be welded to the second piece byutilizing the outer weld collar portion which is easily supported, asufficient strength can be easily secured in welding the first andsecond pieces to each other.

Accordingly, in the resin intake manifold in accordance with the presentinvention, even in the case that the tank chamber formed over threewelded pieces is integrally provided, the weld cost and man-hour arehardly increased. Therefore, it is possible to manufacture the resinintake manifold while restricting the increase of the manufacturingman-hour and cost.

Even in the case that the inner weld collar portion is structured so asto protrude to the inner portion of the peripheral wall portion, sincethe inner weld collar portion is provided in the tank chamber forming noflow passage of the intake fluid, there is no risk that no influence isapplied to the flow of the intake fluid.

Further, the structure may be made such that the peripheral wall portionof the first piece is formed in a forward tapered shape from the outerweld collar portion to the inner weld collar portion along an axialdirection. In accordance with this structure, an end portion of theperipheral wall portion in the side of the inner weld collar portion canmake an outer shape small, and it is possible to further prevent theinterference with the pressurizing jig supporting the outer weld collarportion at a time of welding the first piece to the second piece, sothat it is possible to stabilize the support of the outer weld collarportion of the first piece, and it is possible to improve a weldstrength between the first and second pieces.

Even in the case that the peripheral wall portion is formed in theforward tapered shape from the outer weld collar portion to the innerweld collar portion along the axial direction, the capacity of theperipheral wall portion can be secured as large as possible. In otherwords, in the end portion of the forward tapered peripheral wallportion, since the inner weld collar portion is provided in an innerperipheral side, the outer peripheral side portion of the peripheralwall portion at the position can be arranged at an outer position asclose to the position extending along the axial direction of theperipheral wall portion in the outer weld collar portion as possible,within a range in which the taper shape can be maintained. Therefore, itis possible to arrange the end portion of the peripheral wall portion inthe side of the inner weld collar portion as close to an outer side in aradial direction of the peripheral wall portion as possible, and it ispossible to secure the capacity of the peripheral wall portion large.

Further, in the case that the intake flow passage formed by the firstpiece forms a part of the surge tank, it is desirable that the tankchamber is arranged in a space between the surge tank and a dischargeport of the intake flow passage. In accordance with the structurementioned above, it is possible to arrange the tank chamber in a deadspace between the surge tank and the discharge port of the intake flowpassage, and it is possible to structure the intake manifold providedwith the tank chamber compact. Further, even in the case that the tankchamber is provided in the dead space mentioned above, not only thewelding between the first and third pieces in the peripheral portion ofthe tank chamber, but also the welding between the first and secondpieces can be executed while stably supporting the weld portions by apredetermined pressurizing jig, so that it is possible to sufficientlysecure the strength and it is possible to easily carry out the weldingoperation.

In this case, the welding operation in accordance with the presentinvention is constituted by a vibration welding of welding whilepressurizing by utilizing a friction heat caused by the vibrationincluding a supersonic welding or the like, and is carried out by usingthe pressurizing jig supporting the pieces so as to vibrate the pieceswhile pressurizing.

A third object of the present invention is to provide a resin intakemanifold which can improve a pressure resisting strength and a vibrationresisting strength, and can restrict a ventilation resistance of theintake air caused by the weld line.

The third object can be achieved by a resin intake manifold having thefollowing structure. In accordance with the present invention, there isprovided a resin intake manifold having a plurality of pieces formed ina predetermined shape and welded along a weld line, a surge tank and anindependent intake passage connected to the surge tank, wherein a funnelportion is formed in a portion connected from the surge tank to theindependent intake passage, the weld line is formed so as to cross overa portion near the funnel portion, a funnel partition wall separating aplurality of independent intake passages is formed in the funnel portionso as to protrude from one piece to another piece, a funnel wallreceiving portion receiving the funnel partition wall is formed inanother piece, and the funnel partition wall and the funnel wallreceiving portion are welded in bonded surfaces.

In this case, it is preferable that the funnel partition wall of thefunnel portion is formed in an approximately triangular shape such thata corner portion protrudes to another piece side. It is preferable thatan approximately V-shaped folded weld line is formed in an edge portionof the funnel partition wall in the funnel portion.

The resin intake manifold having the structure mentioned above ismanufactured in such a manner that a plurality of pieces are formed in apredetermined shape by a synthetic resin, and the pieces are weldedalong the weld line in accordance with the vibration welding or thelike. The surge tank and a plurality of independent intake passageconnected thereto are formed in the inner portion of the resin intakemanifold, the funnel portion is formed in the portion connected from thesurge tank to the independent intake passage, the funnel partition wallis formed in the funnel portion so as to protrude from one piece toanother piece, and the weld line is formed and welded in the bondedsurface of the funnel partition wall.

Accordingly, the weld line formed so as to cross over the funnel portionis not formed as a flat line on a flat surface, but is formed as athree-dimensional shape. Therefore, in the case that the intake manifoldis attached to the engine and used, and the vibration caused by thevibration of the engine and the pulsation of the intake air are appliedto the funnel portion, it is possible to effectively inhibit adeformation in a three-dimensional direction of the portion, and it ispossible to improve a pressure resisting strength and a vibrationresisting strength of the portion and an entire manifold. Further, sincethe step which tends to be generated in the inner wall of the intakepassage within the funnel portion by the weld line is formed in adirection approximately extending along the ventilation direction whichis different from the transversal direction of the intake passage, it ispossible to reduce the ventilation resistance of the intake air.

Further, the structure may be made such that the funnel partition wallof the funnel portion is formed in an approximately triangular shapesuch that the corner portion protrudes to another piece side, or anapproximately V-shaped folded weld line is formed in an edge portion ofthe funnel partition wall in the funnel portion. In accordance with thisstructure, it is possible to further improve the pressure resistingstrength and the vibration resisting strength, and it is possible toreduce the ventilation resistance of the intake air.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a view explaining a conventional vibration welding time;

FIG. 1B is a view describing a welding process to which a conventionalembodiment is applied;

FIG. 2 is a plan view of a resin intake manifold in accordance with afirst embodiment of the present invention;

FIG. 3 is a bottom elevational view of the intake manifold;

FIG. 4 is a view showing a left side elevational view of the intakemanifold and an exploded state thereof;

FIG. 5 is a vertical cross sectional view of the intake manifold andcorresponds to a portion along a line V-V in FIG. 2;

FIG. 6 is a bottom elevational view of a cover member of the intakemanifold;

FIG. 7 is a plan view of abase member of the intake manifold;

FIG. 8 is a view explaining a vibration welding time of the intakemanifold;

FIG. 9 is a view explaining a vibration welding time of the otherportion of the intake manifold;

FIG. 10 is an enlarged cross sectional view showing a vibration weldingstructure in accordance with a modified embodiment of the intakemanifold;

FIG. 11 is a view explaining a vibration welding time of a portion ofthe structure shown in FIG. 10;

FIG. 12 is a plan view of a resin intake manifold in accordance with asecond embodiment of the present invention;

FIG. 13 is a bottom elevational view of the intake manifold;

FIG. 14 is a view showing a left side elevational view of the intakemanifold and an exploded state thereof;

FIG. 15 is a vertical cross sectional view of the intake manifold andcorresponds to a portion along a line V-V in FIG. 13;

FIG. 16 is a vertical cross sectional view of the intake manifold andcorresponds to a portion along a line VI-VI in FIG. 13;

FIG. 17 is a vertical cross sectional view of the intake manifold andcorresponds to a portion along a line VII-VII in FIG. 13;

FIG. 18 is a bottom elevational view showing a first piece of the intakemanifold;

FIG. 19 is a plan view showing the first piece of the intake manifold;

FIG. 20 is a bottom elevational view showing a second piece of theintake manifold;

FIG. 21 is a plan view showing a third piece of the intake manifold;

FIG. 22 is a view explaining a time of welding the first piece to thethird piece;

FIG. 23 is a front elevational view of a resin intake manifold inaccordance with a third embodiment of the present invention;

FIG. 24 is a back elevational view of the intake manifold;

FIG. 25 is a right side elevational view of the intake manifold;

FIG. 26 is a left side elevational view of the intake manifold;

FIG. 27 is a plan view of a first piece 2 of the intake manifold;

FIG. 28 is a back elevational view of the first piece 2 of the intakemanifold;

FIG. 29 is a perspective view of a funnel portion in the first piece 2of the intake manifold;

FIG. 30 is a front elevational view of a third piece 4 of the intakemanifold;

FIG. 31 is a front elevational view of the third piece 4 of the intakemanifold;

FIG. 32 is an exploded left side elevational view of the intakemanifold;

FIG. 33 is an exploded right side elevational view of the intakemanifold; and

FIG. 34 is an exploded cross sectional view of the intake manifold.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will be given below of the present invention on the basisof an embodiment shown in the accompanying drawings. In this case, thedescription is not limited to the embodiment. All modifications withinthe contents of claims or equivalents relating to the contents areincluded within the scope of claims.

FIGS. 2 to 11 show a resin intake manifold in accordance with a firstembodiment. A resin intake manifold I is constituted by four separatedbodies which are respectively formed by a thermoplastic synthetic resinsuch as 6 nylon with filler or the like and comprise a cover member 21,a base member 31 positioned below the cover member 21, a tank andresonator combined member 43 positioned below the base member 31, and aresonator bottom member 45, as shown in FIGS. 2 to 5. Further, theintake manifold I in accordance with the embodiment is assembled betweena throttle body (not shown) and a cylinder head side of an engine, andis structured such that a flow passage 11 of an intake fluid F (refer toFIG. 5), and a resonator 19 communicated with a part of the intake flowpassage 11 are provided.

The intake flow passage 11 is structured such as to be provided with asurge tank 14 positioned in an upstream side, and distribution passages15 for distributing an intake fluid F from the surge tank 14 torespective cylinders of the engine. The distribution passages 15 areintegrally assembled in a lower portion in a side of a base portion 15 acorresponding to a back surface side of the intake manifold I, and arestructured such that a side of a leading end corresponding to a frontsurface side of the intake manifold I is separated into a plurality ofleading end portions 15 b so as to freely flow the intake fluid Ftherethrough. In the case of the embodiment, four distribution passagesare arranged in parallel in a lateral direction.

In this case, the fluid F passing through the throttle valve is flowedinto the intake flow passage 11 from an intake port 12 (refer to FIG.7), and is discharged from four discharge ports 13 so as to pass throughthe surge tank 14 of the intake flow passage 11 and the distributionpassages 15 and flow into the engine side. The intake port 12 isarranged in a right end side of the intake manifold I so as to be opento a diagonally upper side, and a flange portion 17 connected to a sideof a throttle body (not shown) is formed in the periphery of the intakeport 12. Each of the discharge ports 13 is arranged so as to be open toa downward direction in a front surface side of the intake manifold I,and a flange portion 18 connected to a side of an engine (not shown) isformed in the periphery of each of the discharge ports 13.

The surge tank 14 is arranged such as to extend approximately in acylindrical shape from the intake port 12 to a left side by setting theside of the intake port 12 to a right end side. Four distribution ports16 (refer to FIGS. 5 and 7) communicating with the respectivedistribution passages 15 are arranged in parallel in a back surface sideof the intake manifold I in the surge tank 14, in the side of the baseportions 15 a of the respective passages 15. Each of the distributionpassages 15 is arranged so as to extend from a back surface side of theintake manifold I toward an upper surface side, and extend from theupper surface side to a lower (the leading end portion 15 b) side in afront surface side. In other words, the fluid F flowing from the intakeport 12 flows to a left side from a right end side of the surge tank 14,flows into each of the distribution passages 15 from each of thedistribution ports 16 toward the upper side, flows from a back surfaceside of the intake manifold I to an upper surface side so as to flowspirally in each of the distribution passages 15, and flows to adownward side in the front surface side, thereby flowing out from eachof the discharge ports 13, as shown in FIGS. 5 and 7.

The resonator 19 is arranged in a space between the surge tank 14 in aleft end side of the intake manifold I and the discharge port 13 of theintake flow passage 11 in such a manner as to make a communication port(not shown) open to a lower portion side near a middle of the surge tank14 in a lateral direction and arrange a communication passage 20 (referto FIGS. 3 and 5) extending to a left side in a bottom surface side ofthe intake manifold I from the communication port.

Further, the intake manifold I is manufactured by vibration welding therespective members 21, 31, 43 and 45. The intake manifold I ismanufactured first by previously forming an upper member U obtained byvibration welding the cover member 21 and the base member 31, and alower member D obtained by vibration welding the tank resonator combinedmember 43 and the resonator bottom member 45, and vibration welding thebase member 31 and the combined member 43, thereby connecting the upperand lower members U and D.

The bottom member 45 is arranged as a member for resonator covering abottom portion side of the communication passage 20 and the resonator19, and an upper member 42 of the resonator bottom member 45 is formedas a tank and resonator combined member for forming a lower portion sideof the surge tank 14 and the resonator 19.

The base member 31 in an upper side of the combined member 42 isstructured, as shown in FIGS. 5 and 7, such that a recess grooveddistribution passage portion 35 forming a lower portion side of each ofthe distribution passages 15 is arranged in an upper surface side, asurge tank portion 32 forming an upper portion side of the surge tank 14and an upper portion of the resonator 19 are formed in a lower surfaceside, and a ceiling wall portion 34 closing the upper end side of theresonator 19 is arranged. Four distribution ports 16 are open to thedistribution passage portion 35 in a back surface side of the intakemanifold I, and four discharge ports 13 are open to a front surface sideof the intake manifold I.

A weld portion 37 for welding to the cover member 21 is arranged in aperipheral edge of the distribution passage portion 35 in the basemember 31 so as to form four distribution passages 15. The weld portion37 is structured, as shown by a dark color in FIG. 7, such that anupward protruding protrusion 38 is provided, and recess grooves 40 and41 are formed in an inner peripheral side and an outer peripheral sideof the protrusion 38 (refer to FIG. 8). The recess groove 41 is formeddeeper than the recess groove 40 in such a manner as to receive anextension portion 29 of a cover wall 28 mentioned below.

The cover member 21 is a member for forming an outer wall of each of thedistribution passages 15, as shown in FIGS. 4 to 6 and 8, and isstructured such that the cover member 21 is provided with an assembledportion 22 integrally covering the side of the base portions 15 a of therespective distribution passages 15, and branch portions 23 arranged soas to extend to the side of the leading end portions 15 b of therespective distribution passages 15 from the assembled portion 22,corresponding to the number of the respective distribution passages 15and separated from each other. Further, a weld portion 24 provided witha protrusion 25 in a protruding manner is arranged in an outerperipheral edge, in a lower surface of the cover member 21, incorrespondence to the protrusion 38 of the weld portion 37 in the basemember 31, as shown in by a dark color in FIG. 4. The weld portion 24 isstructured such that the weld portion 24 is provided with the protrusion25, and cover walls 27 and 28 arranged in an inner peripheral side andan outer peripheral side of the protrusion 25 with an interval H withrespect to the protrusion 25.

A vibrating direction D at a time of vibration welding between the covermember 21 and the base member 31 is set to a lateral direction along theparallel arranging direction of the respective distribution passages 15,the protrusion 25 of the weld portion 24 makes a parallel protrusionportion 26 extending along the vibrating direction D to be arranged inthe leading end 23 a of each of the branch portions 23 in the covermember 21, and the protrusion 38 of the weld portion 37 is also providedwith a parallel protrusion portion 39 extending along the vibratingdirection D in correspondence to the parallel protrusion portion 26. Inthis case, in the embodiment, the parallel protrusion portions 26 and 39extending along the vibrating direction D are arranged also in the sideof the assembled portion 22 of the cover member 21.

Further, an extension portion 29 having a leading end (a lower end) 29 aextended to a lower side than the outer cover wall 27 is arranged in theinner cover wall 28 of the protrusion 25 so as to be arranged at aposition orthogonal to the vibrating direction D in the parallelprotrusion portion 26. The extension portion 29 is arranged so as toprevent the burr B generated at a time of welding the parallelprotrusion portions 26 and 39 from getting over the cover wall 27. Alength L of the extension portion 29 protruding from the leading end 25a of the protrusion 25 before being welded is set in correspondence to amoving speed to the side of the recess groove 41 and a generation stateof the burr B in such a manner that even in the case that the burr B isgenerated at a time when the leading end 29 a of the extension portion29 moves so as to be received within the recess groove 41, a leading endBT of the burr B is brought into contact with an inner side surface 29 bof the extension portion 29 so as to be in a state of being preventedfrom getting over the extension portion 29.

In this case, in the side of the leading end 23 a of each of the branchportions 23, a set reference surface PT1 corresponding to a referencefor designing the protrusions 25 and 38 and the cover walls 27 and 28 ata time of welding the weld portions 24 and 37 to each other is formed ina downward bulged circular arc shape, while taking into considerationthe die cutting direction of the base member 31 and the connectingdirection between the cover member 21 and the base member 31 inconsideration of the inner peripheral surface of the discharge port 13,as shown in FIG. 8. Further, in the side of the assembled portion 22, aset reference surface PT2 of the weld portions 24 and 37 is formed in aninclined surface in which an inner side corresponding to the side of thedistribution passage 15 is made higher in an upper side than an outerside, as shown in FIG. 9, while taking into consideration the diecutting direction of the cover member 21 near the weld portions 24 and37 and the connecting direction between both the members 21 and 31.

Further, in manufacturing the intake manifold I in accordance with theembodiment, as mentioned already, there is a step of previously formingthe upper member U obtained by welding the cover member 21 and the basemember 31, and the lower member D obtained by welding the tank resonatorcombined member 43 and the resonator bottom member 45.

At this time, when forming the upper member U, the base member 31 is setto a predetermined jig for vibration welding, the cover member 21 is setto an upper side of the base member 31, and the cover member 21 ispressed and vibrated along the direction D by a predeterminedpressurizing jig. Then, the protrusions 25 and 38 are molten and weldedin the weld portions 24 and 37 between the corresponding cover member 21and base member 31, and a lot of burrs are generated in the portion ofthe parallel protrusion portions 26 and 39.

However, in the side of the leading end 23 a of the branch portion 23 inthe cover member 21, as shown in FIGS. 8A and 8B, even when the burr Bgenerated by the melting between the leading ends 25 a and 38 a of theprotrusions 25 and 38 is going to extend in an approximately orthogonaldirection from the parallel protrusion portions 26 and 39 so as to getover the cover wall 28 during the welding step, the extension portion 29formed in the cover wall 28 so as to extend to the opposite base member31 welded to the cover member 21 provided with the cover wall 28 stopsthe burr B by the inner surface 29 b, and prevents the burr B from beingexposed to the inner peripheral side of the intake manifold I.

Further, in the case that the welding is finished, since the extensionportion 29 is arranged in the recess groove 41 of the opposite basemember 31 as shown in FIG. 8C, and the burr B can be stayed in a space Sin the side of the parallel protrusion portion 26 of the extensionportion 29, it is possible to prevent the burr B from being scattered,even when the burr B is arranged in the inner peripheral side of theintake manifold I.

In the same manner, in the side of the assembled portion 22 of the covermember 21, as shown in FIGS. 9A and 9B, even when the burr B generatedby the melting between the leading ends 25 a and 38 a of the protrusions25 and 38 is going to extend in an approximately orthogonal directionfrom the parallel protrusion portions 26 and 39 so as to get over thecover wall 28 during the welding step, the extension portion 29 formedin the cover wall 28 stops the burr B by the inner surface 29 b, andprevents the burr B from being exposed to the inner peripheral side ofthe intake manifold I. Further, in the case that the welding isfinished, since the extension portion 29 is arranged in the recessgroove 41 of the opposite base member 31 as shown in FIG. 9C, and theburr B can be stayed in the space S in the side of the parallelprotrusion portion 26 of the extension portion 29, it is possible toprevent the burr B from being scattered, even when the burr B isarranged in the inner peripheral side of the intake manifold I.

The resin intake manifold I in accordance with the embodiment can bemanufactured by forming the upper member U and thereafter vibrationwelding the tank resonator combined member 43 and the base member 31 inthe previously formed lower member D.

Accordingly, in the resin intake manifold in accordance with theembodiment, it is possible to easily prevent the burr B generated at atime of vibration welding the cover member 21 and the base member 31from being exposed to the inner peripheral side of the product I, onlyby arranging the extension portion 29, and it is possible to prevent theburr B from being scattered. It is possible to lower the manufacturingman-hour and cost at a degree that the inspection of presence of theburr B and the burr removing process can be simplified. Of course, sincethe burr B is not exposed to the inner peripheral side of the product Ieven in a state in which the set reference surfaces PT1 and PT2 of theweld portions 24 and 37 between the cover member 21 and the base member31 corresponding to the separated bodies are arranged in the curvedshape or the inclined shape, it is possible to freely set the diecutting direction at a time of molding the separated bodies 21 and 31themselves and the connecting direction between the separated bodies 21and 31 with no limitation by the burr B, and it is possible to improve adesign freedom of the cover member 21 and the base member 31corresponding to the separated bodies.

Further, in particular, in accordance with the embodiment, the vibratingdirection D at a time of vibration welding the cover member 21 and thebase member 31 is set to the lateral direction along the parallelarranging direction of the respective distribution passages 15, and theparallel protrusion portions 26 and 39 and the cover wall 28 providedwith the extension portion 29 are arranged in the leading end 23 a ofeach of the branch portions 23 in the cover member 21. In other words,in the cover member 21 mentioned above, an entire area of the weldportion 24 including the assembled portion 22 and the respective branchportions 23 is pressed and supported by the pressurizing jig used forvibration welding so as to be weld to the weld portion 37 of theopposing base member 31, at a time of vibration welding. However, theleading end 23 a of each of the branch portions 23 is separated fromeach other and tends to be dispersed in the dimensional accuracy incomparison with the assembled portion 22. As a result, the dispersion isgenerated in the weld margin for welding, and the portion generating theburr B tends to be generated further, in addition to the matter thatthis portion is in the parallel protrusion portions 26 and 37 tending togenerate the burr B. However, in the embodiment, since the cover wall 28provided with the extension portion 29 is arranged in the portiontending to generate the burr B, it is possible to accurately cover theburr B.

Of course, even in the case that the vibrating direction D is set to thelateral direction extending along the parallel arranging direction ofthe respective distribution passages 15 at a time of welding, and therespective distribution passages 15 are arranged spirally in the outerperipheral side of the intake manifold I from the upstream side of theintake fluid F to the downstream side, the cover member 21 can besmoothly vibrated so as to be welded to the base member 21, in the caseof the embodiment. In the case of setting the vibrating direction D ofthe vibration welding to the approximately orthogonal direction to theparallel arranging direction of the respective distribution passages 15,that is, the longitudinal direction of the intake manifold Icorresponding to the direction extending along the respectivedistribution passages 15, the entire area of the weld portions 25 and 37is not in contact smoothly, it is hard to properly generate the frictionheat and it is impossible to vibration weld.

Further, in the embodiment, the cover wall 28 provided with theextension portion 29 is arranged in the inner side of the respectivedistribution passages 15 in the parallel protrusion portions 26 and 39,there is no risk that the burr B is scattered into the distributionpassage 15, and it is possible to prevent an engine trouble caused bythe burr B.

In this case, the embodiment shows the case that the cover wall 28provided with the extension portion 29 is arranged in the inner side ofthe respective distribution passages 15 in the parallel protrusionportions 26 and 39, however, the cover wall 28 provided with theextension portion 29 may be arranged in an outer side of the parallelprotrusion portions 26 and 39 as far as the cover wall 28 provided withthe extension portion 29 is arranged in a side to which the burr B tendsto be extended. For example, as shown in FIG. 10, in the assembledportion 22 of the cover member 21, a set reference surface PT3 of theweld portions 24 and 37 can be formed as an inclined surface in which aninner side corresponding to the side of the distribution passage 15 ismade lower than an outer side, in consideration of the die cuttingdirection of the cover member 21 near the weld portions 24 and 37, andthe connecting direction of both the members 21 and 31. In the case ofthis structure, even when the burr B generated by the welding betweenthe leading ends 25 a and 38 a of the protrusions 25 and 38 is going toextend in the approximately orthogonal direction from the parallelprotrusion portions 26 and 39 so as to get over the cover wall 28 duringthe welding step, at a time of vibration welding the weld portions 24and 37, as shown in FIGS. 11A and 11B, the extension portion 29 formedin the cover wall 28 stops the burr B by the inner surface 29 b, andprevents the burr B from being exposed to the outer peripheral side ofthe intake manifold I, and it is possible to manufacture the intakemanifold I with an improved outer appearance design.

In the case of a structure shown in FIGS. 10 and 11, that is, in thecase that the set reference surface PT2 of the weld portions 24 and 37is an inclined surface in which the inner side corresponding to the sideof the distribution passage 15 is made lower than the outer side, thecover wall 27 is in a state of being provided with the extension portionin the leading end 27 a, on the basis of an angle of incline, and it ispossible to stop the burr B extending to the inner side in the side ofthe distribution passage 15. In view of this matter, the extensionportion 29 may be arranged in both sides comprising the inner side andthe outer side of the parallel protrusion portion 26.

FIGS. 12 to 22 show a second embodiment in accordance with the presentinvention. A resin intake manifold I in accordance with the secondembodiment is constituted by four separated bodies which arerespectively formed by a thermoplastic synthetic resin such as 6 nylonwith filler or the like and comprise a first piece 121, a second piece135, a third piece 132 and a fourth piece 146, as shown in FIGS. 12 to17. Further, the intake manifold I in accordance with the secondembodiment is assembled between a throttle body (not shown) and acylinder head side of an engine, and is structured such that a flowpassage 111 of an intake fluid F (refer to FIG. 6), and a tank chamber119 communicated with a part of the intake flow passage 111 areprovided. Further, the intake flow passage 111 is structured such as tobe provided with a surge tank 114 positioned in an upstream side, anddistribution passages 115 for distributing an intake fluid F from thesurge tank 114 to respective cylinders of the engine. The tank chamber119 in accordance with the second embodiment is structured as aresonator 119 communicated with the surge tank 114 so as to intend anoise reduction and an improvement of an output torque. Further, fourdistribution passages 115 are arranged in the case of the embodiment.

The fluid F passing through the throttle valve is flowed into the intakeflow passage 111 from an intake port 112, and is discharged from fourdischarge ports 113 so as to pass through the surge tank 114 of theintake flow passage 111 and the distribution passages 115 and flow intothe engine side. The intake port 112 is arranged in a right end side ofthe intake manifold I so as to be open to a diagonally upper side, and aflange portion 117 connected to a side of a throttle body (not shown) isformed in the periphery of the intake port 112. Each of the dischargeports 113 is arranged so as to be open to a downward direction in afront surface side of the intake manifold I, and a flange portion 118connected to a side of an engine (not shown) is formed in the peripheryof each of the discharge ports 113.

The surge tank 114 is arranged such as to extend approximately in acylindrical shape from the intake port 112 to a left side by setting theside of the intake port 112 to a right end side. Four distribution ports116 communicating with the respective distribution passages 115 arearranged in parallel in a back surface side of the intake manifold I inthe surge tank 114. Each of the distribution passages 115 is arranged soas to extend from a back surface side of the intake manifold I toward anupper surface side, and extend from the upper surface side to a lowerside in a front surface side. In other words, the fluid F flowing fromthe intake port 112 flows to a left side from a right end side of thesurge tank 114, as shown in FIGS. 15, 19 and 20, flows into each of thedistribution passages 115 from each of the distribution ports 116 towardthe upper side, as shown in FIG. 16, flows from a back surface side ofthe intake manifold I to an upper surface side in each of thedistribution passages 115, and flows to a downward side in the frontsurface side, thereby flowing out from each of the discharge ports 113.

Further, the resonator 119 is arranged in a space between the surge tank114 in a left end side of the intake manifold I and the discharge port113 of the intake flow passage 111 in such a manner as to make acommunication port 124 a open to a lower portion side near a middle ofthe surge tank 114 in a lateral direction and arrange a communicationpassage 124 extending to a left side in a bottom surface side of theintake manifold I from the communication port 124 a (refer to FIG. 20).

Further, the arrangement of four respective pieces 121, 132, 135 and 146is structured such that the third piece 132, the first piece 121, thesecond piece 135 and the fourth piece 146 are arranged in sequence fromthe bottom portion side of the intake manifold I. The intake manifold Iis manufactured by vibration welding the respective pieces 121, 132, 135and 146. The intake manifold I is manufactured first by previouslyforming an upper member U obtained by welding the fourth piece 146 andthe second piece 135, and a lower member D obtained by welding the firstpiece 121 and the third piece 132, and vibration welding the first piece121 and the second piece 135, thereby connecting the upper and lowermembers U and D.

Further, as shown in FIGS. 12 and 14 to 16, the fourth piece 146constitutes an upper cover member sectioning and covering the upperportion side of each of the distribution passages 115. Further, thesecond piece 135 is structured, as shown in FIGS. 14 to 16, such that arecess grooved distribution passage portion 139 forming a lower portionside of each of the distribution passages 115 is arranged in an uppersurface side, a surge tank portion 136 forming an upper portion side ofthe surge tank 114 and an upper portion of the resonator 119 are formedin a lower surface side, and a ceiling wall portion 138 closing theupper end side 123 a of the peripheral wall portion 123 of the resonator19 in the first piece 121 is arranged.

In a lower surface side of the second piece 135, as shown in FIGS. 16and 20, the surge tank portion 136 and the ceiling wall portion 138 arearranged with holding a common wall portion 135 a therebetween. Further,a portion to which a dark color is applied in FIG. 20 corresponds to aweld portion 141 to the first piece 121. The first piece weld portion141 including a lower end surface of the common wall portion 135 a isarranged in a lower end surface of a wall portion in the surge tank 136and a lower end surface of the ceiling wall portion 139, and is providedwith a protrusion 141 a melting in a leading end (a lower end) at a timeof welding. Further, the weld portion 141 is structured as an outwardprotruding weld collar portion 142 as shown in FIGS. 12, 14 to 16 and20, in right and left side surface portions and a back surface portionof the intake manifold I.

The first piece 121 is structured such that the first piece 121 isprovided with a main body wall portion 122 forming the lower portionside of the surge tank 14, as shown in FIGS. 13, 15, 18 and 19, and aperipheral wall portion 123 having an approximately square tubular shapefor forming the resonator 119. A recess grooved communication passage124 communicating with the resonator 119 is arranged in a lower surfaceof the first piece 121, as shown in FIGS. 15, 16 and 18, and acommunication port 124 a penetrating vertically is open to a right endof the communication passage 124, as shown in FIGS. 15, 18 and 19. Theresonator peripheral wall portion 123 is provided with a wall portion121 a commonly used with the main body wall portion 122, and is formedin a taper shape tapered toward the lower end 123 b as shown in FIG. 17.

A second piece weld portion 125 is arranged in an upper surface side ofthe first piece 121, as shown by a dark color in FIG. 19, incorrespondence to the first piece weld portion 141 of the second piece135 so as to be welded to the second piece 135. The weld portion 125 isconstituted by an outer weld collar portion 126, a common wall portionweld portion 127, and a distribution port portion weld portion 128. Theouter weld collar portion 126 is arranged in an entire periphery of anouter peripheral edge of the first piece 121 including the peripheralwall portion 123, and is formed so as to protrude to an outer side. Thecommon wall portion weld portion 127 is arranged on an upper end surfaceof the common wall portion 121 a. Further, the distribution port portionweld portion 128 is arranged in a peripheral edge of each of thedistribution ports 116. A protrusion 125 a melting in a leading end (anupper end) at a time of welding is formed in the weld portion 125 (126,127, 128). In this case, the common wall portion weld portion 127 isstructured as a weld collar portion 127 protruding to an innerperipheral surface of the peripheral wall portion 123, as shown in FIGS.16 and 18.

A third piece weld portion 129 is arranged in a lower surface side ofthe first piece 121, as shown by a dark color in FIG. 18, in such amanner as to be welded to the third piece 132, and a protrusion 129 amelting in a leading end (a lower end) at a time of welding is formed inthe weld portion 129. Further, the third piece weld portion 129 isstructured as an inner weld collar portion 130 protruding to an innerperipheral surface side of the peripheral wall portion 123 in the otherportions than the portion of the common wall portion 121 a in theresonator peripheral wall portion 123, as shown in FIGS. 17 and 19, andis arranged in an inner peripheral side of the peripheral wall portion123 so as to prevent the portion of the weld collar portion 130 frombeing interfered with a pressurizing jig 152 supporting the outer weldcolor portion 126 at a time of welding the second piece weld portion 125of the first piece 121 to the first piece weld portion 141 of the secondpiece 135. In this case, as shown in FIGS. 16 and 18, the portion 131 ofthe common wall portion 121 a in the weld portion 129, it is arranged ina lower end surface of the common wall portion 121 a without protrudingto inner and outer peripheries of the peripheral wall portion 123.Further, in a portion apart from the peripheral wall portion 123 of theweld portion 129, it is arranged in the lower surface of the main bodywall portion 122, as shown in FIGS. 15 and 16.

The third piece 132 is arranged in a bottom surface of the intakemanifold I as shown in FIGS. 13 to 17 and 21, and is structured as acover member closing a side of the end portion 123 b in a lower side ofthe peripheral wall portion 123 in the resonator 119. In the embodiment,not only the lower side of the peripheral wall 123 itself, but also thelower side of the communication passage 124 including the communicationport 124 a is covered. An upper surface side of the outer peripheraledge in the third piece 132 is provided with a protrusion 133 a meltingin a leading end (an upper end) at a time of welding, and a weld portion133 welded to the third piece weld portion 129 of the third piece 121 isformed therein.

In manufacturing the intake manifold I in accordance with theembodiment, as already mentioned, there is first a step of previouslyforming the upper member U obtained by welding the fourth piece 146 andthe second piece 135, and the lower member D obtained by welding thefirst piece 121 and the third piece 132. At this time, as shown in FIG.22A, the lower member D can be formed by reversing the taperedperipheral wall portion 123 tapered to the end portion 123 b in thefirst piece 121 up and down, setting the peripheral wall portion 123 soas to be fitted to the pressurizing jig 148, setting the third piece 132in the upper side thereof, bringing the weld portions 125 and 133 intocontact with each other, setting the pressurizing jig 149 to the upperside of the third piece 132 as shown in FIG. 22B, pressing thepressurizing jig 149 to the lower side, vibrating the pressurizing jig149, and welding the weld portions 129 and 133 to each other. Further,after forming the upper member U and the lower member D, the intakemanifold I can be manufactured by utilizing pressurizing jigs 151 and152, or the like and vibration welding the second piece weld portion 125of the first piece 121, and the first piece weld portion 141 of thesecond piece 135, as shown by a two-dot chain line in FIGS. 15 and 17.

Further, in the resin intake manifold I in accordance with the secondembodiment, even in the case that the outer weld collar portion 126 forwelding to the second piece 135 is provided in one end portion 123 a ofthe peripheral wall portion 123 in the first piece 121, the weld portion129 to the third piece 132 in another end portion 123 b of theperipheral wall portion 123 is formed as the inner weld collar portion130 which can prevent an interference with the pressurizing jig 52supporting the outer weld collar portion 126 at a time of welding thefirst piece 121 to the second piece 135.

Accordingly, at a time of welding the first piece 121 to the third piece132, as shown in FIG. 22, the inner weld collar portion 130 of theperipheral wall portion 123 can be supported by the pressurizing jig 148arranged in the inner peripheral side of the peripheral wall portion123. Since the pressurizing jig 148 can be formed as a simple structurewhich is not necessary to be slid, the welding cost is not increased,and the inner weld collar portion 130 can be firmly supported in theinner peripheral side of the peripheral wall portion 123, it is notnecessary to increase the weld time unnecessarily and the weldingman-hour is not increased.

Of course, since the first piece 121 can be welded to the second piece135 by utilizing the outer weld collar portion 126 which is easilysupported by the pressurizing jig 152, it is possible to easily secure asufficient strength in welding the first and second pieces 121 and 135to each other.

Accordingly, in the resin intake manifold I in accordance with thesecond embodiment, even in the case that the resonator 119 correspondingto the tank chamber formed over three welded pieces 121, 135 and 132 isintegrally provided, the increase of the welding cost and man-hour isrestricted as much as possible. Accordingly, it is possible tomanufacture the intake manifold I while restricting the increase of themanufacturing man-hour and cost.

Even in the case that the inner weld collar portion 130 is structuredsuch as to protrude to the inner portion of the peripheral wall portion123, the inner weld collar portion 130 is provided in the tank chamber119 which does not structure the fluid passage 111 of the intake fluidF, and there is no risk that an influence is exerted to the flow of theintake fluid F.

Further, in the embodiment, the peripheral wall portion 113 of the firstpiece 121 is formed in a forward tapered shape from the outer weldcollar portion 126 extending along the axial direction to the inner weldcollar portion 130. Accordingly, the end portion 123 b of the peripheralwall portion 123 in the side of the inner weld collar portion 130 can bemade small in an outer shape thereof, and it is possible to furtherprevent the interference with the pressurizing jig 152 supporting theouter weld collar portion 126 at a time of welding the first piece 121to the second piece 135. As a result, the pressurizing jig 152 canstabilize the support of the outer weld collar portion 130 of the firstpiece 121, and can improve a welding strength between the first andsecond pieces 121 and 135.

In this case, even in the case that the peripheral wall portion 123 isformed in the forward tapered shape from the outer weld collar portion126 extending along the axial direction to the inner weld collar portion130, the capacity of the peripheral wall portion 123 can be secured aslarge as possible. In other words, since the inner weld collar portion130 is provided in an inner peripheral side in the end portion 123 b ofthe forward tapered peripheral wall portion 123, the outer side portion123 c (refer to FIG. 17) of the peripheral wall portion 123 at theposition can be arranged at an outer position up to a position close tothe position along the axial direction of the peripheral wall portion123 in the outer weld collar portion 126 as close as possible within therange that can maintain the taper shape. Accordingly, it is possible toarrange the end portion 123 b of the peripheral wall portion 123 in theside of the inner weld collar portion 130 in an outer side of theperipheral wall portion 123 in a radial direction as close as possible,and it is possible to secure the capacity of the peripheral wall portion123 large.

Further, in the embodiment, the intake flow passage 111 formed by thefirst piece 121 is structured such as to form a part of the surge tank114, the resonator 119 is arranged in a dead space between the surgetank 114 and the discharge port 113 of the intake flow passage 111, andthe intake manifold I provided in the resonator 119 can be structuredcompact. Further, even in the case that the resonator 119 is provided inthe dead space, it is possible to stably support the weld portion by thepredetermined pressurizing jigs 148, 149, 151 and 152, not only in thewelding between the first and third pieces 121 and 132 in the peripheralwall portion 123 of the resonator 119, but also in the welding betweenthe first and second pieces 121 and 135. Accordingly, it is possible tosufficiently secure the strength and it is possible to easily carry outthe vibration welding.

In the case, in the intake manifold I in accordance with the embodiment,there is shown the case that the intake manifold I is structured by fourpieces 121, 132, 135 and 146, however, the present invention can beapplied to the resin intake manifold structured by three pieces or fiveor more pieces.

Further, in the present embodiment, the resonator 119 is exemplified asthe tank chamber provided in the intake manifold I, however, the surgetank, an accumulator tank communicated with a diaphragm chamber or thelike can be additionally exemplified as the tank chamber, and thepresent invention can be applied thereto.

FIGS. 23 to 34 show a third embodiment in accordance with the presentinvention. FIG. 23 shows a front elevational view of a resin intakemanifold 201 used in an in-line four-cylinder engine, FIG. 24 shows aback elevational view of the same, FIG. 25 shows a right sideelevational view of same, and FIG. 26 shows a left side elevational viewof the same.

The resin intake manifold 201 is constituted by a first piece 202positioned in a center portion, a second piece 203 forming a coverportion of an independent intake passage in an upper portion, a thirdpiece 204 positioned in a back surface portion of the first piece andforming a back surface side of a surge tank 224, and a fourth piece 205positioned in a back surface portion of the third piece 204 and forminga cover portion of a resonator 225. Members of the first piece 202, thesecond piece 203, the third piece 204 and the fourth piece 205 areformed in a predetermined shape in accordance with an injection moldingof synthetic resin, and are welded along a weld line ML in accordancewith a vibration welding or the like, whereby the resin intake manifold201 is formed.

The first piece 202 constituting a center portion of the rein intakemanifold 201 has a cylinder side mounting flange 220 fixed to a cylinderside (a cylinder head side) of the engine, as shown in FIGS. 27 to 29,intake air introduction port 221 for four cylinders are provided inparallel in the cylinder side mounting flange 220, and mounting holes220 a for fixing are formed in a plurality of positions in an edgeportion. Further, a portion forming a half shell portion of the surgetank 224 is formed in a back surface side of the first piece 202, andhalf shell portions of four independent intake passage 226 communicatedwith the surge tank 224 are formed in a front surface side of the firstpiece 202.

A throttle side mounting flange 222 for fixing a throttle valveapparatus is formed in a front surface of the first piece 202 close to aleft side, as shown in FIG. 23. An intake air introduction port 223 isformed in the throttle side mounting flange 222, and mounting holes 222a are formed in a plurality of positions in an edge portion thereof. Theintake air introduction port 223 is communicated with the surge tank 224within the first piece 202.

Further, the throttle side mounting flange 222 is positioned in a sideportion of the cylinder side mounting flange 220, and a plate-shaped andL-shaped connection portion is integrally formed between the throttleside mounting flange 222 and the cylinder side mounting flange 220 so asto connect the throttle side mounting flange 222 to the cylinder sidemounting flange 220.

As shown in FIG. 27, a weld line ML for welding the second piece 203forming a cover wall 231 of the upper independent intake passage 226 isformed in the front surface side of the first piece 202 along an outershape portion of the independent intake passage 226, and as shown inFIG. 28, a weld line ML for welding the third piece 204 forming a backsurface side of the surge tank 224 is formed in the back surface side ofthe first piece 202 along an outer shape portion of the surge tank 224.

Further, as shown in FIGS. 28 and 29, a funnel portion 227 forming aninlet is formed in a portion connected to the independent intake passage226 from the surge tank 224, and the weld line ML is formed near thefunnel portion 227. A thick funnel wall 228 is formed in an edge portionof the funnel portion 227, and a funnel partition wall 229 separatingfour independent intake passages 226 is formed in the funnel portion 227so as to protrude from the first piece 202 to the third piece 204 in anapproximately triangular shape, as shown in FIG. 29.

The third piece 204 is formed so as to form an outer shell portion in aback surface side of the surge tank 224 in a back surface side of thefirst piece 202, as shown in FIGS. 30 and 31, a surge tank portion 243forming a part of the surge tank 224 is formed in a recessed shapethere, and a resonator portion 241 communicated with the surge tankportion 243 through a communication passage 245 is formed. Further, asshown in FIG. 31, a funnel wall receiving portion 244 for receiving thefitted funnel partition wall 229 is formed in the third piece 204, and aweld line ML is formed in a joint surface between the funnel partitionwall 229 and the funnel wall receiving portion 244.

Further, the funnel partition wall 229 of the funnel portion 227 isformed in an approximately triangular shape in which a corner portionprotrudes to the third piece 204 side, as shown in FIG. 29, and a weldline ML bent approximately in a C shape is formed in an edge portion ofthe funnel partition wall 229. Further, as shown in FIG. 31, the weldline ML is also formed in an edge portion of the funnel wall receivingportion 244 in the third piece 204.

On the other hand, as shown in FIGS. 32 and 33, the second piece 203 isformed in a shape forming the cover wall 231 of the independent intakepassage 226 in the front side of the first piece 202, and is formed in ashape covering each of upper portions of four independent intakepassages 226, and an outer edge portion is brought into contact with theweld line ML of the first piece 202 in the front side and is welded.

The forth piece 205 forming an outer shell portion of the resonator 241is formed as a cover member in a back surface side of the resonatorportion 241 in the third piece 204, and is welded to the back surfaceside of the third piece 204. An EGR pipe mounting flange 242 formounting an EGR pipe is provided in a right side portion of the thirdpiece 204.

Members of the first piece 202, the second piece 203, the third piece204 and the fourth piece 205 having the structures mentioned above arebonded to each other as shown in FIGS. 32 to 34, a bonded portion alongthe weld line is welded thereto in accordance with a vibration welding,and the resin intake manifold 201 is manufactured.

The resin intake manifold 201 having the structure mentioned above isused by fixing the cylinder side mounting flange 220 to a cylinder headside of the engine (not shown), fixing a throttle valve apparatus (notshown) to the throttle side mounting flange 2.22, and connecting pipearrangements such as EGR pipes or the like, sensors and the like.

At a time of operating the engine, the air sucked into the engine isfiltrated by an air cleaner, thereafter passes through the throttlevalve apparatus, is introduced into the resin intake manifold 1 from theintake air introduction port 223, and enters into the surge tank 224.Further, the air passes through the independent intake passage 226connected to a downstream side of the surge tank 224, and is distributedto each of the cylinders of the engine through the intake airintroduction port 221.

At a time of supplying the intake air mentioned above to each of thecylinders, a vibration is generated by a pressure pulsation generatedwithin the resin intake manifold 1 in correspondence to the opening andclosing operation of the throttle valve, and the vibration transmittedfrom the engine block is generated in the resin intake manifold 201.

However, particularly in the joint portion between the first piece 202and the third piece 204 constituting the main portion, the funnelpartition wall 229 of the funnel portion 227 in the first piece 202positioned near the center portion thereof is formed in theapproximately triangular shape such that the corner portion protrudes tothe side of the third piece 204, and the weld line ML formed in the edgeportion of the funnel partition wall 229 is welded in athree-dimensional shape.

Accordingly, even in the case that vibration of the engine or thevibration caused by the pulsation of the intake air is applied to thefunnel portion or the entire of the manifold, at a time of using theintake manifold, it is possible to effectively restrict a deformation ofthe portion in a three-dimensional direction, and it is possible toimprove a pressure resisting strength and a vibration resisting strengthof the portion and the entire of the manifold.

Further, the air sucked at a time of using is distributed to each of thecylinders of the engine through the independent intake passage 226connected to the downstream side of the surge tank 224 and through theintake air introduction port 221, however, since the step generated onthe inner wall of the intake passage within the funnel portion 227 bythe weld line is formed the direction approximately extending along theventilating direction which is different from the transversal directionof the independent intake passage 226, it is possible to restrict andreduce the ventilation resistance of the intake air.

As described above, in accordance with the resin intake manifoldmentioned above, the weld line formed so as to cross over the funnelportion is not formed as the flat line on the flat surface, but isformed as the three-dimensional shape. Accordingly, in the case that theintake manifold is attached to the engine and used, and the vibrationcaused by the vibration of the engine and the pulsation of the intakeair are applied to the funnel portion, it is possible to effectivelyinhibit the deformation in the three-dimensional direction of theportion, and it is possible to improve the pressure resisting strengthand the vibration resisting strength of the portion and the entiremanifold. Further, since the step which tends to be generated in theinner wall of the intake passage within the funnel portion by the weldline is formed in the direction approximately extending along theventilation direction which is different from the transversal directionof the intake passage, it is possible to reduce the ventilationresistance of the intake air.

1. A resin intake manifold comprising: a surge tank; and independentintake passages connected to said surge tank; wherein a plurality ofpieces formed in a predetermined shape is combined and the jointportions thereof are formed by welding along a weld line, a funnelportion is formed in a portion connected from said surge tank to theindependent intake passages, the weld line is formed so as to cross overa portion near said funnel portion, said weld line having athree-dimensional shape where it crosses over the portion near saidfunnel portion, funnel partition walls separating a plurality ofindependent intake passages are formed in said funnel portion so as toprotrude from one piece to another piece, wherein funnel wall receivingportions receiving said funnel partition walls are formed in saidanother piece, said funnel partition walls in one piece are formed in anapproximately triangular shape, a corner of said triangular shapeprotrudes within the funnel portion of the surge tank in another piece,one side of the triangular shape is in contact with said funnel wallreceiving portion, and said funnel partition walls are welded to saidfunnel wall receiving portions, the weld lines of said funnel partitionwalls are connected to the weld line of the outer wall portion whichcrosses over a portion near the funnel portion of said surge tank, andwherein the weld line which comprising the weld line of the outer wallportion of said surge tank and the weld lines of said funnel partitionwalls are formed in a three-dimensional shape.
 2. A resin intakemanifold as claimed in claim 1, wherein an approximately V-shaped foldedweld line is formed in an edge portion of the funnel partition wall insaid funnel portion.